Tensor Network Path Integral Study of Dynamics in B850 LH2 Ring with Atomistically Derived Vibrations

Area of Science:

• Quantum mechanics
• Spectroscopy
• Biophysics

Background:

• The B850 bacteriochlorophyll ring is crucial for light harvesting in purple bacteria.
• Simulating quantum dynamics in complex biological systems is computationally challenging.
• Dissipative environments significantly influence exciton dynamics.

Purpose of the Study:

• To apply the multisite tensor network path integral (MS-TNPI) method to a realistic biological system, the B850 ring.
• To investigate exciton transport and absorption spectrum of the B850 ring.
• To assess the accuracy of MS-TNPI against approximations and explore temperature effects.

Main Methods:

• Utilizing the multisite tensor network path integral (MS-TNPI) for quantum system simulation.
• Incorporating molecular dynamics for vibrations and protein scaffold interactions via Feynman-Vernon influence functional.
• Simulating absorption spectra with approximate and topologically consistent transition dipole moments.

Main Results:

• Numerically exact MS-TNPI simulations of exciton transport and absorption spectra for the B850 ring.
• Comparison of MS-TNPI results with second-order cumulant approximations.
• Analysis of temperature-dependent effects on both exact and approximate spectra.

Conclusions:

• MS-TNPI provides a powerful and accurate tool for simulating extended quantum systems like the B850 ring.
• The study highlights the importance of including vibrational and topological details for accurate spectral predictions.
• MS-TNPI offers a pathway to understanding energy transfer mechanisms in photosynthetic complexes.